Remove in-container healthchecks for Airflow

Summary:
CPU spikes through docker exec healthcheck feature use
are too important: 132% with a curl every 30 seconds,
vs 5% without for example.

Do the same curl call from outside don't create any spike,
so the CPU cost is clearly the one to log the process,
prepare the documents like JSON configuration or payloads
events for its lifecycle start, attach, stop.

As such, focus will be on out-of-container checks.

See https://github.com/moby/moby/issues/39102 for discussion.

Ref T1812

Test Plan: On Dwellers, CPU usage dropped swiftly to <3% most of the time.

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1812

Differential Revision: https://devcentral.nasqueron.org/D2950